MCP: sandbox tools hide after onboarding

An agent connected to a hosted Motorical MCP server no longer sees the sandbox tools (motorical_sandbox_status, motorical_sandbox_provision, motorical_sandbox_convert and the motorical_free_recipient_* tools) once your account has a verified domain of its own, an active plan, and has moved out of the sandbox (converted it, or gone straight to production). They only exist to get a new account to its first real send, so after that they were noise that invited wrong calls.

• The rule needs all three. A Free account on its own domain is still in the sandbox and keeps these tools until it has a plan, and an account with a domain and a plan keeps them until the sandbox is converted, because converting is its next step.
• It changes what an agent is told about, not what your account may do. Reconnecting is not needed; the next time the client lists tools it sees the shorter list.
• The local @motorical/mcp server is unchanged.